1993 toyota tercel

I have a 1993 toyota tercel that has a strange problem. The car starts fine when the engine is cold. If I drive it 15 to 20 minutes and stop and then try to start it again it will either not start or if it does, it makes a putting noise and shakes. Also if this is happening and I turn the steering wheel, the car will stop. Help, I took it to the best mechanic in my city and they are perplexed, thanks for any advice.

Does it start normally if you start it right away or overnight?
If so, it likely is due to a leaky injector. Try running some fuel injector cleaner or gas system cleaner through a full tank of gas. Techron is a good brand. Sometimes it needs to be done more than once to fully clear it out.

The reason it’s puffing and shaking is that it’s barely running. Something has become heat sensitive. I believe the '93 Tercel is a coil-on-plug (COP) system, and chances of all four coils becoming sensitive simultaneously is small, but there are other things like the crankshaft position sensor and the EFI main relay that are in the engine compartment and might be becoming heat sensitive.

The reason I suspect heat sensitivity is because it happens after you shut down following a 20 minute drive. When yo shut down the temperature under the hood rises as the heat from around the cylinders and the exhaust manifold and system dissipate out the sides of the engine and components. These items are hundreds of degrees hotter than the underhood temperature when you’re driving along with air flowing through the area.

The reason its stops when you turn the wheel is that by virtue of turning you’re causing the power steering pump to put an added load on a barely operating engine. Fix the sputtering and the stopping will disappear.

The best mechanic in the city should not be perplexed. Try the second best mechanic in the city.

Yeah, that is another very good explanation.

Regardless, any mechanic worth his salt should be able to figure that one out.

I suspect something is adversely affecting the fuel/air mixture when the engine is hot.

Idea 1: It is running too lean when hot. When the engine is cold, the ECU injects extra gas. But as the engine heats up, the ECU realizes this from the coolant sensor, and reduces the amont of gas. If there is an air leak somewhere, any air that gets past the MAF sensor unmeasured, like a vaccuum leak,intake manifold leak, this confuses the ECU, and yields too low fuel/air mixture, which will cause the car not to run smoothly, or in some cases not at all. Ask your mechanic to test all the vacuum hose and devices for leaks. Sounds like a lot of work, but it is actually very easy with the right tool, takes 15 minutes maybe.

Idea 2: EGR is stuck open. The EGR is supposed to be closed at idle. Sometimes it sticks open. Or the vacuum switching device is stuck “on” and that opens the EGR when it isn’t supposed to be open. This should produce a “check engine” DTC. Is the check engine light on?

Idea 3: Cold start injector malfunction. This device injects extra gas at start-up only when the engine is cold. But if it or somethng which controls it fail, it will inject extra gas when the engine is hot too. This would cause the symptom you are describing. Ask you mechanic to check the cold start injector function.

There are other things that could cause this. Maybe the spark plugs or the distributor cap are worn and the timing and idle speed adjustment is off and it just needs a tune-up is all. In any event, I’d recommend you get all the routine maintenance items suggested in your owner’s manual brought up to date if you’d like to keep your car running reliably.

Best of luck.

The problem might be with a sticky Idle Air Control valve. The IAC valve controls the engine idle speed depending on the load imposed on the engine. For example, when the AC is turned on the IAC valve bumps the idle speed up so the load the AC compressor puts on the engine doesn’t cause the engine to stall. Or when turning the steering wheel, a pressure switch in the power steering system sends a signal to the computer to bump the idle up to prevent the engine from stalling from the load imposed from the power steering pump.

Sometimes the IAC valve can be removed and cleaned along with the idle air bleed port on the throttle body of gum, varnish, and carbon to free it up. Or, sometimes the IAC valve just requires replacement.